1. Field of the Invention
The present invention relates to a neck crystallization system that is suitable for a wide-mouth container, and the like.
2. Description of the Related Art
A wide-mouth (wide-neck) container has a configuration in which the ratio of the outer diameter of the neck to the outer diameter of the body is larger than that of a narrow-mouth (narrow-neck) container (e.g., polyethylene terephthalate (PET) bottle) that is widely used as a beverage container. For example, a container having a neck outer diameter of 43 mm or more may be referred to as “wide-mouth container”. The wide-mouth container has been widely used as a solid (e.g., jam) container in addition to a liquid container since it is easy to remove the contents from the wide-mouth container.
When the wide-mouth container is to be subjected to a high-temperature filling operation, it is necessary to increase the density of the neck through crystallization so that the neck exhibits heat resistance.
A system that crystallizes the neck of a molded article has been proposed. Japanese Patent No. 3842067 discloses technology that crystallizes the neck of a preform that is to be blow-molded, cools the neck using a cooling core that is inserted into the heated neck, and transfers the preform removed from a transfer member. Japanese Patent No. 4266686 discloses technology that attaches a shield member to a transfer member to prevent heat from a heater from being applied to an area other than the neck.
In both of the prior arts, the molded article that is subjected to neck crystallization is transferred along a track-like transfer path that includes two linear transfer paths that are parallel to the long side of a stage having a rectangular shape in a plan view, and is formed by fitting a chain around one drive sprocket and one driven sprocket. The heating section is disposed along the two linear transfer paths.
However, since the number of molded articles that can be disposed in the track-like transfer path, and the number of molded articles that are heated by the heating section decrease as the (neck) diameter of the molded article that is subjected to neck crystallization increases, it is necessary to increase the length of the long side of the stage. As a result, the system becomes elongated due to an increase in the ratio of the long side to the short side, and it is difficult to design the system layout within a factory where a plurality of systems are installed. Moreover, since the distance between the drive sprocket and the driven sprocket increases as the length of the long side increases, it is necessary to take measures for preventing deflection of the endless member (e.g., chain) that transfers the preform, for example.
In Japanese Patent No. 3842067, an area in which the heating section is disposed is provided along the linear transfer path by disposing the cooling section in an arc-like transfer path. However, since it is necessary to dispose at least the molded article supply section in the linear transfer path, the heating section placement space decreases correspondingly.
In FIG. 1 of Japanese Patent No. 4266686, the heating section placement space in the linear transfer path similarly decreases due to the presence of the molded article supply section and the like. In FIG. 1 of Japanese Patent No. 4266686 in which wide-mouth containers are arranged, the number of molded articles that can be subjected to neck crystallization further decreases as compared with FIG. 1 of Japanese Patent No. 3842067 in which narrow-mouth preforms are arranged. It is necessary to decrease the molded article transfer speed when the length of the heating zone is not increased. This results in a decrease in throughput of neck crystallization.